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Topic: Low power sensor node: Arduino Pro Mini 3.3V and/or Standalone ATmega328P (Read 165 times) previous topic - next topic

edwardwetrust

For my project, I will need low power wireless sensor nodes. These parts will be powered off battery, so the most minimal power consumption is desired. Some requirements were:
1. Minimal power consumption because it will be battery powered
2. Voltage minimum is 3.2V for the sensors/wireless modules
3. Voltage maximum is 5.5V because I do not want to use a voltage regulator (and ATmega328P can only tolerate up to 5.5V from its datasheet)


From googling, the two best approaches for minimal power consumption seemed to be:

1. Using a standalone ATmega328P board with unneeded LEDs, voltage regulators, etc. removed/not included
2. Using an Arduino Pro Mini 3.3V 8MHz with the LEDs and voltage regulator physically removed

I'll be experimenting both approaches. Both will be at 3.3V 8MHz to further minimize power consumption, while still meeting minimum voltage requirements. After some googling, it also seemed that both approaches at 3.3V 8MHz should work with 3 AA batteries in series (for 4.5V nominal), connected to their unregulated voltage pin Vcc. Is this correct/will this work?

I was also wondering how would I program both. Since they will be both at 3.3V 8MHz, I was planning to use:

https://www.sparkfun.com/products/9873

I just wanted to make sure, will this work for both the Arduino Pro Mini 3.3V 8MHz and the standalone ATmega328P also at 3.3V 8MHz?


Some google results said leaving the Arduino IDE settings for Arduino Pro Mini 3.3V 8MHz will work for both the Pro Mini and my proposed standalone ATmega328P 3.3V 8MHz set-up. However, I couldn't find much tutorials on the standalone ATmega328P at 3.3V 8MHz because most were for the 5V 16MHz.

Lastly, I'm not sure how to configure the ATmega328P for 3.3V 8MHz. I ordered it online from an electronics supplier, and I don't think it will come with a bootloader. Is there like a 3.3V bootloader? How do I configure the ATmega328P to be 3.3V 8MHz?

Any help or suggestions for my project and/or possible alternative directions for it would be appreciated! Thank you.

groundFungus

4.5V will work fine for a 3.3V 8MHz stand alone 328.

The FTDI will work for Serial programming.  You will need programmer or another Arduino running the Arduino as ISP sketch to bootload the processors.

I use the MiniCore core to bootload processors for 8MHz operation.

Here is a very good article on making a standalone 328 low power.

WattsThat

Don't overlook the overall system voltage requirements, not just the processor as some sensors are 3.3 volts maximum.
Vacuum tube guy in a solid state world

edwardwetrust

Don't overlook the overall system voltage requirements, not just the processor as some sensors are 3.3 volts maximum.
Woops, forgot to mention that in my post, but yeah their maximum voltages are a bit more tolerant (up to 7V).

WattsThat

Woops, forgot to mention that in my post, but yeah their maximum voltages are a bit more tolerant (up to 7V).
Then you're good to go at 3 volts. As GF mentioned, you'll need a programmer to get a bootloader onto a blank chip. The easiest and most cost effective way to do this is to purchase a USBASP on eBay, about $5 when paired with the necessary 6 pin adapter. I'm a fan of the units with the plastic enclosure as shown.

Vacuum tube guy in a solid state world


PaulRB

The easiest and most cost effective way to do this is to purchase a USBASP on eBay, about $5 when paired with the necessary 6 pin adapter.
I second the USBasp suggestion, but the 6 pin adaptor is not "necessary". I have that adaptor and have never used it. It could be useful for re-burning bootloaders on Uno, Nano etc. but Pro Mini and atmega328 dip chips don't have a 6-pin interface anyway. So don't pay more for the adaptor would be my advice.

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